An atomic layer deposition method is a method for forming a thin film on a substrate on an atomic layer basis by alternately supplying, on the substrate, gases of elements constituting the thin film to be formed to, and is known as a technique for uniformly forming a thin film. The atomic layer deposition method is excellent in step coverage and film thickness controllability, compared to a general CVD (Chemical Vapor Deposition) method.
In a conventional sputtering film deposition device, a mask can be utilized, as described in Patent Literature 1. In sputtering film deposition, step coverage of a film is low, and therefore an amount of film deposition on a back side of a mask is small. Accordingly, a particle generation amount is small, and a maintenance cycle is also long. However, in atomic layer deposition method, step coverage of a film is high, and therefore an amount of film deposition on a back side of a mask is large. Gas that enters a micro clearance becomes a thick film and powder, which causes particles. Particularly, surface roughness of a mask cannot be increased in order to maintain flatness of the mask, and therefore replacement frequency of the mask is increased.
Therefore, in the atomic layer deposition method using a mask, inert gas purge from a periphery of a susceptor is effective. In Patent Literature 2, a gas supply port is provided in a stage, and inert gas is supplied from a back side of a susceptor.